In UMTS (Universal Mobile Telecommunications System) cell reselection, a user equipment (UE) typically stays in the 3G radio access technology as long as there is coverage. Only when the 3G coverage vanishes, does a User Equipment (UE) camp on the 2G radio access technology (GSM or GPRS). This means that a subscriber using a 3G phone will camp on 3G unless 3G coverage vanishes. Because cell reselection policies favour camping on the “newest” (i.e. implemented most recently) radio access technology, this causes camping loading and traffic loading tend to be accumulated in the newest Radio Technology.
With the introduction of 4th Generation (4G) radio technology, the mobile networks have to handle the co-existence of different Radio Technologies such as UMTS-UTRAN (Universal Mobile Telecommunication System-Radio Access Network), Higher Speed Packet Access technologies (HSPA, HSPA+, etc.) implemented in UMTS and Long Term Evolution (LTE) technology, among others, in addition to the existing 2G technologies: the coverage from each of these technologies may substantially overlap.
The multi-RAT mobile network operators have to select the most suitable RAT (Radio Access Technology) for delivering services to any given subscriber at any given time, taking account of such issues as whether the subscriber's mobile terminal or User Equipment (UE) is in the idle state or in a connected mode.
Therefore, a Mobile Network Operator (MNO) may decide to direct the subscriber first to 3G, even if the LTE coverage is good enough, for several reasons (e.g. CS call setup time, efficiency in resource management, network stability); when it does so, each UE is initially connected to 3G radio access. As a consequence, the UE supporting 3G and LTE shows a 3G indication in the display of the terminal. From the user's point of view, this displayed 3G indicator could lead to the impression that the LTE network is deficient or that the terminal is not capable of connecting to LTE. From the point of view of service provisioning, once the decision of connection to 3G, instead of 4G, is taken by the MNO, the UE cannot be aware of the 4G coverage and, hence, certain services such as those requiring high-speed access can be affected negatively. There can be scenarios in which the initial selected radio technology, which the UE is camped on, is not the optimal one for carrying the service.
Today it is possible to implement (in the display of the UE) an indication of the current radio technology (2G, 3G) upon which the UE is camped and whether this technology is able to offer GPRS and/or HSPA. This current capability of the UE is pretty obvious as the UE is already attached to the technology displayed. However, it is not possible to obtain information in one RAT about the signal or presence of other RATs, in order to receive indication and display it in the UE.
There is therefore a need to optimise service provision, especially provisioning of high-speed communication services, in wireless networks where multiple radio technologies (2G, 3G, 4G, . . . ) provide overlapping coverage to different subscribers, each technology providing their own coverage and Quality of Service (QoS) and subscribers having mobile terminals (User Equipments) which are capable of supporting every technology.